The rear station and train breakdown centre (CDT)

Almost invisible to passengers but essential to the operation of the line: their location is one of the major subjects of the consultation.

What is it for?

Rear Station : This completely underground extension of the tracks beyond the terminus station allows trains to turn around and park outside of service hours.
Train Breakdown Centre (CDT): Directly connected to the line, it allows trains to be repaired quickly (less than 1 hour) and avoid service interruptions, especially during rush hour. Underground, it would require limited access on the surface.

Why new installations?

The current train breakdown centre for Metro 1, at Porte Maillot, would be too far from the new terminus. The workshops in Fontenay-sous-Bois are dedicated to the heavy maintenance of five metro lines (1, 4, 6, 11 and 14) and cannot accommodate this new function. A new centre is therefore essential. The operation of the extended line would also require 12 additional trains, 100% financed by Île-de-France Mobilités.

Des variantes de localisation soumises au débat

The rear station, invisible on the surface, would be located beyond the terminus of Val de Fontenay. Its precise location and that of the train breakdown centre (mostly underground) is the subject of several variants (in the sectors of Fontenay-sous-Bois, Neuilly-Plaisance, Paris and on the edge of Rosny-sous-Bois). They are compared according to their impact on land, land use planning and work conditions. This is one of the major choices discussed during the consultation.

Variante A : Implantation du CDT à Fontenay-sous-Bois

This variant is limited to the territory of Fontenay-sous-Bois, offering a curved rear station. The framework structure housing the train breakdown centre should then be widened and lengthened. In this variant, this structure serves as a tunnel boring machine starting shaft (as in the initial scenario).

Variante B : CDT utilisé comme puits de sortie de tunnelier

Compared to the initial scenario of 2022, this solution provides for the tunnel boring machine entrance shaft at the Val de Fontenay hub and the train breakdown centre at the end of the rear station to the east (with a smaller surface footprint). The operating logic of the tunnel boring machine would be as follows:

Assembly and launch of the tunnel boring machine from the Val de Fontenay cluster.
Tunnel boring machine digging from the rear station to the train breakdown centre to the east.
Removal and dismantling of the tunnel boring machine at the train breakdown centre.
Construction of the open-air train breakdown centre.
Reinsertion of the tunnel boring machine at the Val de Fontenay entrance shaft.
Digging with a tunnel boring machine of the rest of the extension to the west to the Bois de Vincennes, then exiting the tunnel boring machine in the Bois de Vincennes sector.

Variante C : CDT dans les infrastructures existantes de Château de Vincennes

Variant C is based on the principle of variant B:

positioning of the tunnel boring machine's entrance shaft at the Val de Fontenay station
excavation with a tunnel boring machine to the east to build the rear station
Exit of the tunnel boring machine on a reduced right-of-way to the east
reinsertion of the tunnel boring machine from the Val de Fontenay pole to dig westwards to the Bois de Vincennes, then exit of the tunnel boring machine in the Bois de Vincennes sector.

The main distinction in this variant: the functionalities of the train breakdown centre would be located at the level of the existing rear station of Château de Vincennes (in the existing north tunnel). This variant C of the Val de Fontenay rear station is only compatible with variant 3 of the insertion in the Bois de Vincennes

These two provisions combined would:

to limit the site footprints (and its impacts) as much as possible;
to preserve the Fontaine du Vaisseau Economic Activity Zone in Neuilly-Plaisance;
to free itself from the construction of a new framework structure for the train breakdown centre.
The rear station tunnel, about 725 m long, would be entirely dedicated to turning and storage.